There is not just one country that can boast a model but any
country that has a significant research activity is involved
in climate simulation,

If a scientific team came to the conclusion, after having conducted
serious simulation work (serious means reviewed by their peers,
then published in a first rank scientific paper), that Earth
will not "heat up" in response to human induced greenhouse
gases emissions (a conclusion that is almost 2 centuries old, by the way), it would become world famous in a second (and
would be a serious candidate for the Nobel Prize !), and one
can be sure that many people tried very hard to achieve (properly
of course) such a result.

One of the experiences performed to test the models if of course to check that they correctly account for what has really happened (below).

The above charts picture, for each region of the world and for the 1905-2005 period (and, at the bottom, for the whole world, the global land, and the global ocean):

with a black line, the decadal mean (or more exactely the difference between the decadal mean and the 1901-1950 mean) for the whole region, obtained from observations (dotted lines correspond to very little data available).

the pink zone corresponds to the enveloppe of 58 simulations performed with 14 different models when all forcings are taken into account (that is everything that happened is acounted for: volcanoes, solar irradiance, etc, AND human emissions of greenhouse gases),

the blue zone corresponds to the enveloppe of 19 simulations performed with 5 different models assuming all forcing are taken into account, except human emissions of greenhouse gases (a bit as if our emissions never happened).

Two major conclusions derive from this graph:

models correctly account for what really happened, thus backing the idea that they give reliable trends for the future (but those trends will always remain dependant on hypotheses on future emissions),

The scientific
community now considers that any person asserting that human greenhouse
gases emissions are of no importance to the climate must demonstrate
this affirmation.

As of today, no team (because
modelling is team work) has published in a scientific paper results
that would question the main qualitative
conclusions of climate models (what does not prevent, from
time to time, an individual who never published anything in a
scientific paper to try to dismiss
simulations in front of a camera or in a newspaper. So be
it...).

A first indication on the relative
fiability of models comes from the following operation: instead
of studying the future, to know what will happen later, the model
can be used to "study the past", which means that the
run starts from 1860 instead of starting from 2000, in order to
compare the output of the model with the instrumental data (1860
corresponds to the beginning of sufficient instrumental data to
know what was happening on the surface of earth).

Even though the models do not
reproduce exactely year by year values, they quite faithfully
reproduce all the pluriannual trends, that is trends that last
for a couple years or more.

There are other recent evolutions
that match the results of simulations:

temperatures now rise faster during winter than during summer
(what models foresee),

a number of models have been tested on Mars and Venus, where
they account properly for what is observed ; Venus has a climate
system simpler than that of earth (no ocean, no ice caps, no
biosphere) but includes a very specific phenomenum in its atmosphere
(that rotates much faster than the planet itself) which is correctly
reproduced by models.

on our good old planet, climate models also properly account
for the location of the main climatic zones (no tropical climate
in the middle of the south pole !), the rythm of the seasons,
the pluriannual oscillations (El Nino, NAO...), the oceanic and
atmospheric various currents (jet streams, trade winds, Gulf
Stream...), etc.

The scientific community has therefore
a very high degree of confidence in the climate models for their
main qualitative conclusions, including the fact that earth will
globally warm up in response to the additionnal greenhouse effect
due to our industrial civilization. That does mean, of course,
that everything is settled: an intense research activity still
goes on to ameliorate the models so that they are able to reproduce
more and more detailed evolutions.

But local comparisons (will the
warming be more intense in Germany or in France, for example)
are very difficult to establish, and will probably remain so....until
things really happen !Indeed,
the climate system includes many complex equilibriums, and a small
variation somewhere may have a significant effect later on and
in a remote place.

Apart from a couple of indicators
(average temperature, or average precipitations) on some large
zones (a continent for example), it will never be possible to
have detailed regional forecasts. This is a normal limit
to climate simulation, because the system itself is not foreseeable
on a detailed regional scale (impossible to give a forecast on
what the temperature will be in Hong Kong the 6th of July, 2045
!), and this must not let us think that the general conclusions
are flawed or that there is no danger.

Ruling out simulations because
they are global by nature is alike considering that, if nobody
can give it to the second, it's of no interest to know the approximative
transportation time from Washington to Boston (or it's of no interest
to know the approximative amount on a bank account if it can't
be given to the cent, etc): some forecasts may be impossible
to establish in detail, but are nevertheless reliable and useful
for their main trends and large masses.